The present disclosure relates to a secure electronic structure, and particularly to a structure containing random conductors as a physical unclonable function (PUF) and methods for manufacturing the same.
The ability to identify each electronic system uniquely is a useful feature for electronic security purposes. For example, identification of computers, personal hand held devices, cellular phones, chip cards, and other devices that contain sensitive information can be linked to a security feature of data or software in order to prevent unwarranted breach of security. Developers of electronic systems continuously strive to provide systems and methods that make their products impervious to unauthorized access or use. Communication devices used in the military and security fields are one category of devices that must remain secure despite physical and electrical tampering, while other categories also require this feature.
One approach to solve the above identified problems is to employ a physical unclonable function (PUF) to provide a unique, secure bit, word or function for use in generating security keys. A PUF refers to a structure implementing a random logic that is not reproducible among devices manufactured employing a same process. A PUF may eliminate the need for storage of a public or private key on a device. PUFs are known in the art to be implemented by circuits, components, processes or other entities capable of generating an output, such as a digital bit, word or a function that is resistant to cloning.
While PUFs are useful for security purposes, controlling the manufacturing cost for semiconductor chips is an important issue. In order to minimize the additional cost associated with manufacture of PUFs, it is desirable to fabricate the PUF during standard integrated circuit manufacturing without adding, or minimizing the number of, additional process steps in order to provide the benefit of the PUFs with no, or minimal, increase in the manufacturing cost.